There’s a time for silence and a time for speech. It all depends on the circumstances.
In the famous text named “Ethics of our Fathers” we are taught the importance of both silence and speech. One teaching states that “silence is a fence for (promotes) wisdom” (3:13). A person who is quiet and attentive to what others say and do will have an opportunity to learn new things. In addition, thoughtful silence will help a person avoid speaking slander and gossip, as well as not saying something he will later regret. As Mark Twain said, “It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.”
On the other hand, speaking is essential for productive communication in our everyday lives. A person who thinks before he speaks will likely speak in an intelligent, productive and “kosher” manner. As we are also taught in Ethics of our Fathers, “One who is very shy will not learn” (2:6). If a person doesn’t understand something, how will he learn and understand it unless he speaks up and asks for clarification?
Therefore, being on the quiet side is definitely a positive trait – especially if it’s your nature – as long as you are not afraid to speak up when necessary.